ABSTRACT
Edible bird's nest (EBN) is a kind of natural invigorant with a long history of consumption in Asia, especially in China. EBN is formed by mixing the saliva of swiftlets (Aerodramus) with feathers and other components during the breeding season. Proteins are the most important nutrient in EBN. By studying proteins in EBN, we can not only elucidate their components at the molecular level, but also study their bioactivities. Therefore, it is of great significance to study the proteins in EBN. Previous research on the proteins in EBN was preliminary and cursory, and no one has summarized and analyzed the proteins in EBN and correlated the bioactivities of these proteins with the biological functions of EBN. This article focused on the proteins in EBN, listed the proteins identified in different proteomic studies, and introduced the sources, structures and bioactivities of the most frequently identified proteins, including acidic mammalian chitinase, lysyl oxidase homolog 3, mucin-5AC, ovoinhibitor, nucleobindin-2, calcium-binding protein (MW: 4.5 × 104) and glucose-regulated protein (MW: 7.8 × 104). The properties of these proteins are closely related to the bioactivities of EBN. Therefore, this article can provide inspiration for further research on the efficacy of EBN.
ABSTRACT
OBJECTIVE: To observe the expression of acidic mammalian chitinase(AMCase) in lung tissue of silicosis model rats, and bronchoalveolar lavage fluid(BALF) and serum of patients with occupational pneumoconiosis, and to evaluate the value of AMCase in the early diagnosis of pneumoconiosis. METHODS: i) The specific pathogen free adult male Wistar rats were randomly divided into control group and model group, with 15 rats in each group. The rats in the silicosis model group was exposed to free silica dust with a concentration of 2 000.0 mg/m~3 by dynamic inhalation for three hours a day, while the rats in control group were not exposed to dust. Five rats in the two groups were sacrificed at 4, 12 and 24 weeks after dust exposure. ii) By random number table method, a total of 191 patients with occupational pneumoconiosis who received large capacity lung lavage were selected as the pneumoconiosis group, 12 dust-exposed workers who received large capacity lung lavage were selected as the dust control group, and 200 healthy coal miners exposed to dust were selected as healthy control group. iii) Western blotting was used to detect the relative protein expression of AMCase, type Ⅰ collagen(COLⅠ), α-smooth muscle actin(α-SMA) in lung tissues of the rats and the relative protein expression of AMCase in human BALF. Enzyme linked immunosorbent assay was used to detect the level of AMCase protein in human serum. Receiver operating characteristic(ROC) curve was used to evaluate the value of AMCase protein level in human serum for early diagnosis of pneumoconiosis. RESULTS: The relative expression of AMCase, COLⅠand α-SMA protein in lung tissue of rats in the silicosis model group were higher than that of control group(all P<0.01). The relative expression of AMCase protein in BALF of pneumoconiosis group and pneumoconiosis stage Ⅰ, Ⅱ and Ⅲ subgroups were higher than that of dust control group(all P<0.05). The level of AMCase protein in serum of pneumoconiosis group and pneumoconiosis stage Ⅰ, Ⅱ and Ⅲ subgroups were higher than that of healthy control group(all P<0.05). The results of ROC curve analysis showed that the area under ROC curve was 0.78(95% confidence interval: 0.74-0.82).When the cut-off value of serum AMCase protein level was 466.0 ng/L, the sensitivity was 73.8%, and the specificity was 72.6%. CONCLUSION: AMCase protein in human serum has value for early diagnosis of pneumoconiosis and it could be a potential biomarker for early diagnosis of pneumoconiosis.
ABSTRACT
Objective To clone acidic mammalian chitinase (AMCase) gene and analyze the sequences of the nucleotides and encoded amino acids. Methods Total RNA was isolated from the stomach of BALB/c mouse and the mRNA was reversely transcribed into cDNA. AMCase gene was amplified by polymerase chain reaction and inserted into recombinant clone vector of pMD18-T. Sequence alignment was performed with DNAMAN 4.0 software. Isoelectric point, amino acid composition, signal peptide and transmembrane helices were analyzed with SignalP 3.0 Server and TMHMM Server v.2.0. Results The cloned gene encodes a protein of 473 amino acids with molecular weight of 51.93 kDa and isoelectric point 4.73. Extensive amino acid sequence homology (up to 99.57%) was found when compared with AMCase. Both protein encoded by this cloned gene and AMCase belonged to family 18 chitinase, which was composed of signal peptide (amino acid position 1-21), the catalytic domain (amino acid position 22-391), hinge region (amino acid position 392-425) and chitin binding domain (amino acid position 426-473). There were two mutations of amino acid in the catalytic domain and hinge region with this AMCase mutant. The amino acid of Ala(position 292)was mutated into amino acid of Pro, and the amino acid of Thr(position 404)was mutated into amino acid of Ser. Conclusion This sequence is a mutant of AMCase gene. Identification of the biological characteristics will play important role in the further study of its biological function by molecular biology technique.